Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Hackney]
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Lead content (mg/1. Pb) water from mains taps in consumer's premises
| Number of samples | Per cent | |
|---|---|---|
| Less than 0.01 | 64 | 66.7 |
| 0.01 | 22 | 22.9 |
| 0.02 | 3 | 3. 1 |
| 0.03 | 4 | 4. 2 |
| 0.04 | 2 | 2. 1 |
| 0. 05 | 0 | - |
| 0.06 | 1 | 1.0 |
| 96 | 100.0 |
Results of bacteriological examination after treatment (yearly average)
| Source of supply | No. of samples | Agar Plate Count per ml. after 20-24 hours at 37°C | Coliform count per cent, samples negative in 100 ml. | E. Coli count per cent samples negative in 100 ml. |
|---|---|---|---|---|
| Stoke Newington | 254 | 6. 5 | 99. 61 | 99.61 |
| All Thames Derived | 3.578 | 12. 2 | 99.75 | 99. 97 |
Average results of the chemical examination of water (Milligrams per litre):
| Stoke Newington | All Thames derived | |
|---|---|---|
| No. of samples | 52 | 363 |
| Ammoniacal Nitrogen | 0.017 | 0.024 |
| Albuminoid Nitrogen | 0.063 | 0. 089 |
| Nitrate Nitrogen | 5.2 | 4. 1 |
| Oxygen abs, from KMn04 4 hrs. at 27°C | 0.56 | 1. 12 |
| Hardness (total) CaC03 | 312 | 182 |
| Hardness (non-carbonate) CaC03 | 77 | 73 |
| Magnesium as Mg | 5 | 5 |
| Sodium as Na | 28.9 | 22.5 |
| Potassium as K | 4.8 | 5.1 |
| Chloride as CI | 35 | 30 |
| Phosphate as PO4 | 1.4 | 1.9 |
| Silicate as SiOp2 | 10 | 10 |
| Sulphate as SO4 | 64 | 64 |
| Natural Fluoride as P | 0.30 | 0.30 |
| Surface - active material as Manoxol OT | 0.01 | 0.01 |
| Turbidity units | 0.0 | 0. 1 |
| Colour (Burgess units) | 5 | 12 |
| pH Value | 7.9 | 7.9 |
| Electrical Conductivity (microhms) | 660 | 590 |